drm/msm/mdp5: use drm_plane_state for storing alpha value

Use drm_plane_state's 'alpha' field rather than adding extra 'alpha'
field to mdp5_plane_state.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20210525131316.3117809-3-dmitry.baryshkov@linaro.org
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c

@@ -291,8 +291,8 @@ static void blend_setup(struct drm_crtc *crtc)
 		plane = pstates[i]->base.plane;
 		blend_op = MDP5_LM_BLEND_OP_MODE_FG_ALPHA(FG_CONST) |
 			MDP5_LM_BLEND_OP_MODE_BG_ALPHA(BG_CONST);
-		fg_alpha = pstates[i]->alpha;
-		bg_alpha = 0xFF - pstates[i]->alpha;
+		fg_alpha = pstates[i]->base.alpha >> 8;
+		bg_alpha = 0xFF - fg_alpha;
 
 		if (!format->alpha_enable && bg_alpha_enabled)
 			mixer_op_mode = 0;

drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h

@@ -101,7 +101,6 @@ struct mdp5_plane_state {
 	/* aligned with property */
 	uint8_t premultiplied;
 	uint8_t zpos;
-	uint8_t alpha;
 
 	/* assigned by crtc blender */
 	enum mdp_mixer_stage_id stage;

drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c

@@ -168,7 +168,7 @@ mdp5_plane_atomic_print_state(struct drm_printer *p,
 					      "(null)");
 	drm_printf(p, "\tpremultiplied=%u\n", pstate->premultiplied);
 	drm_printf(p, "\tzpos=%u\n", pstate->zpos);
-	drm_printf(p, "\talpha=%u\n", pstate->alpha);
+	drm_printf(p, "\talpha=%u\n", pstate->base.alpha);
 	drm_printf(p, "\tstage=%s\n", stage2name(pstate->stage));
 }
 
@@ -183,7 +183,6 @@ static void mdp5_plane_reset(struct drm_plane *plane)
 	mdp5_state = kzalloc(sizeof(*mdp5_state), GFP_KERNEL);
 
 	/* assign default blend parameters */
-	mdp5_state->alpha = 255;
 	mdp5_state->premultiplied = 0;
 
 	if (plane->type == DRM_PLANE_TYPE_PRIMARY)